A trial of trastuzumab and anastrozole for advanced breast cancer (BO16216)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 3

This trial was looking at trastuzumab (Herceptin) and anastrozole (Arimidex) for breast cancer that has spread to another part of the body (secondary breast cancer).

Doctors can use hormone therapy, chemotherapy, radiotherapy and biological therapy to treat secondary breast cancer.

Anastrozole is a type of hormone therapy. It is for women who have been through the menopause Open a glossary item and have breast cancer that is hormone receptor positive.

Trastuzumab is a type of biological therapy called a monoclonal antibody. It kills breast cancer cells that make too much of a protein called HER2. This is often referred to as being ‘HER2 positive’.

This trial was comparing anastrozole alone with a combination of anastrozole and trastuzumab. The aims of the trial were to

See if the combination of drugs worked better than anastrozole alone for HER2 positive secondary breast cancer
Learn more about the side effects

Summary of results

The researchers found that the combination of trastuzumab and anastrozole was better than anastrozole alone.

The trial recruited 208 women. They were all post menopausal Open a glossary item and had secondary breast cancer that was HER2 positive. Half the women had a combination of anastrozole and trastuzumab, the other half had anastrozole alone. Later, more than two thirds of the women who only had anastrozole were able to have trastuzumab.

With the combination of both drugs, the cancer responded in just over 20% of the women treated. With anastrozole alone, the cancer responded in just under 7% of the women. And there was a difference in the time it took for the cancer to start growing again. On average, this happened after about

2 and a half months for women having anastrozole alone
5 months for women having anastrozole and trastuzumab

Women having both drugs had more side effects, including damage to the heart. A very small number of women had serious side effects.

9 of the women having both drugs stopped having the treatment because of side effects
1 woman having anastrozole alone stopped treatment because of side effects

The researchers wrote their report in 2006. They are continuing to follow the progress of the women who took part and they may publish results in the future.

We have based this summary on information from the team who ran the trial. As far as we are aware, the information they sent us has not been reviewed independently (peer reviewed Open a glossary item ) or published in a medical journal yet. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.